Preparing oxidized minerals for concentration by froth flotation



Patented Nov. 17, 1931 V UNITED STATES PATENT OFFICE LOCKWOOD W. FERRIS, OF SALT LAKE CITY, UTAH No Drawing.

copper carbonate, copper silicate, metallic copper, and other non-sulfide copper'mi'nerals, may be so conditioned that they are often amenable to concentration by froth flotation, whereas, without the' use of some thiocarbonic acid compound, such minerals cannot be so -concentrated', or else present A xidi d ore f A i carrydifficulties to such concentration.

It is to be clearly understood that the-pres.

actual flotation being accomplished by means of one or more actual flotation agents, such as an oil, amyl xanthate,,and so on.

It should be clear that the thiocarbonic desired condition. Inasmuch as thiocarbonic acid itself is unstable and diflicult to manufacture, its most convenient form is either as a metallic salt, such as sodium thiocarbonate, potassium thiocarbonate, and so on, or an organic salt, such as ethyl 'thiocarbonate, amyl thiocarbonate, and so on. Owing to its convenience, I have preferred to use sodium tri-thiocarbonate, a reaction product between sodium sulfide and carbon bisulfide, as indicated by the following equa tion: Na S plus CS equals Na cs Sulfur may be dissolved in the sodium sulfide, thus making a sodium polysulfide, which gives a better reaction with the carbon Chanel-concentrates acid radical is the agent which creates the Application filed March. 31, 1930. Serial No. 440,621.

bisulfide than does the normal sodium sulfide.

In practicing my improved method, the flotation pulp may be prepared in any usual manner, and be aerated or agitated in any suitable flotation machine. The thiocarbonic acid compound maybe added to the fi0tatron pulp at an suitable stage of the ordinary process of otation, that is to say, either before, at the beginning of, or during agitation or aeration of the pulp.

The amount of thiocarbonic acid and/or compounds thereofl used in my process, depends upon the nature of the particular ore being treated. The relative quantities that may be used, are best illustrated by examples from actual practice. Therefore, I give below the results obtained in the treatment of three ores of different character. These examples are: r

ing about two per cent copper, mostly in the form of silicate: 1

Per cent total copper Tails tails Reagents used per ton of are 1.0 lb. sodium trithiocarbonate. 0.5 lb. amyl xanthate. 0.1 lb. frothing agent.

Assay per cent copper Tails O. 025 Gleaner tails 0. 10 Cleaner concentrates 20. 6

Reagents per ton of are 1.0 lb. sodium trithiocarbonate. 1.0 lb. amyl xanthate. 0.2 lb. frothing agent.

0) An oxidized ore from the Yellow Pine mine at Goodsprings, Nevada:

Assay Per cent per cent tots lead. lead Tails 0. 17 2. 9 Cleaner tails 11. 9 31. 6 Cleaner concentrates 40. 3 65. 5

Reagents used per ton of are 3.0 lbs. sodium silicate.

2.0 lbs. sodium trithiocarbonate. 2.0 lbs. amyl xanthate.

0.1 lb. frothing agent.

In Example (a), the results obtained by means of the present process, indicate a recovery of 81.8 per cent; in Example (6), a recovery of 95.5%; and in Example (0), a recovery of 97.1%.

Having fully described my invention, what I claim is:

1. In the concentration of oxidized ores by froth flotation, the improvement which comprises subjecting the ore in the form of a pulp to the action of an alkali-metal trithiocarbonate.

2. In the concentration of oxidized ores by froth flotation, the improvement which comprises subjecting the ore in the form 01" a pulp to the action of sodium trithiocarbonate.

3. In the concentration by froth flotation of oxidized ores containing silicate and carbonate minerals, the improvement which comprises subjecting the ore in the form of a pulp to the action of sodium trithiocarbonate.

4. In the concentration by froth flotation of oxidized ores containing carbonate minerals, the improvement which comprises subjecting the ore in the form of a pulp to the action of an alkali metal trithiocarbonate.

5. In. the concentration by froth flotation of oxidized ores containing carbonate minerals, the improvement Which comprises subjecting the ore in the form of a pulp to the action of sodium trithiocarbonate.

In testimony whereof, I sign my name hereto.

LOCKWOOD W FERRIS. 

